From 99182ea09f10beca8445396cbab491899536f5c3 Mon Sep 17 00:00:00 2001 From: Xi Ruoyao Date: Fri, 24 Nov 2023 11:08:19 +0800 Subject: Only allow (int)trunc(x) to (int)x simplification with -ffp-int-builtin-inexact [PR107723] With -fno-fp-int-builtin-inexact, trunc is not allowed to raise FE_INEXACT and it should produce an integral result (if the input is not NaN or Inf). Thus FE_INEXACT should not be raised. But (int)x may raise FE_INEXACT when x is a non-integer, non-NaN, and non-Inf value. C23 recommends to do so in a footnote. Thus we should not simplify (int)trunc(x) to (int)x if -fno-fp-int-builtin-inexact is in-effect. gcc/ChangeLog: PR middle-end/107723 * convert.cc (convert_to_integer_1) [case BUILT_IN_TRUNC]: Break early if !flag_fp_int_builtin_inexact and flag_trapping_math. gcc/testsuite/ChangeLog: PR middle-end/107723 * gcc.dg/torture/builtin-fp-int-inexact-trunc.c: New test. --- gcc/convert.cc | 3 ++- gcc/testsuite/gcc.dg/torture/builtin-fp-int-inexact-trunc.c | 12 ++++++++++++ 2 files changed, 14 insertions(+), 1 deletion(-) create mode 100644 gcc/testsuite/gcc.dg/torture/builtin-fp-int-inexact-trunc.c (limited to 'gcc') diff --git a/gcc/convert.cc b/gcc/convert.cc index 46c8bcb..f214b75 100644 --- a/gcc/convert.cc +++ b/gcc/convert.cc @@ -591,7 +591,8 @@ convert_to_integer_1 (tree type, tree expr, bool dofold) CASE_FLT_FN (BUILT_IN_TRUNC): CASE_FLT_FN_FLOATN_NX (BUILT_IN_TRUNC): if (call_expr_nargs (s_expr) != 1 - || !SCALAR_FLOAT_TYPE_P (TREE_TYPE (CALL_EXPR_ARG (s_expr, 0)))) + || !SCALAR_FLOAT_TYPE_P (TREE_TYPE (CALL_EXPR_ARG (s_expr, 0))) + || (!flag_fp_int_builtin_inexact && flag_trapping_math)) break; return convert_to_integer_1 (type, CALL_EXPR_ARG (s_expr, 0), dofold); diff --git a/gcc/testsuite/gcc.dg/torture/builtin-fp-int-inexact-trunc.c b/gcc/testsuite/gcc.dg/torture/builtin-fp-int-inexact-trunc.c new file mode 100644 index 0000000..0973118 --- /dev/null +++ b/gcc/testsuite/gcc.dg/torture/builtin-fp-int-inexact-trunc.c @@ -0,0 +1,12 @@ +/* Test -fno-fp-int-builtin-inexact. */ +/* { dg-do compile } */ +/* { dg-options "-fno-fp-int-builtin-inexact -fdump-tree-original" } */ + +long +x (double y) +{ + return __builtin_trunc (y); +} + +/* Optimization should not discard the __builtin_trunc call. */ +/* { dg-final { scan-tree-dump "__builtin_trunc" "original" } } */ -- cgit v1.1